1. Latitude and Longitude
Angular distance in ° between center of the earth and a point on the earth’s surface
parallels
Longitude
Angular distance in ° east or west of a point on the Earth’s surface
meridians

2. LAT AND LONG
LATITUDE- MEASURES N AND S OF EQUATOR (0 TO 90°) BUT RUNS E AND W
LONGITUDE MEASURES E AND W OF PRIME MERIDIAN (O TO 180°) BUT RUNS N AND S

3. LATITUDE AND LONGITUDE
EQUATOR 0°
NEW ORLEANS
30°N 90°W
90° W 0°

4. Lat and Long Distances Latitude Longitude
69.13 miles ( km) between each degree of latitude
Longitude
Varies by latitude
69 miles at equator only
59.9 miles at 30°
34.6 miles at 60°

5. Lat and Long estimation
Latitude
Can be estimated using the north star (Polaris), or Southern Cross
Longitude
Very tricky
1700’s difference between fixed clock and ship clock

6. TIME ZONES International Date Line
SEPARATES ONE DAY FROM THE NEXT
WHERE THE NEW DAY STARTS
ANY LOCATION EAST OF OUR TIME ZONE UP TO 180° E IS AHEAD OF US
ANY LOCATION WEST OF US UP TO THE DATE LINE (180°) IS BEHIND US
Earth’s rotational speed is approximately 15° longitude/hour
So 24 time zones

7. Time Zones

8. Keeping Time UTC or Z time DST New DST Indiana? London 5 hours ahead
6 on ST
DST
New DST
Not in Arizona, Hawaii
Indiana?
Now observes DST

9. Map Projections Graticule → flat sheet of paper 3D to 2D
distortion in 4 main properties
major – pertains to all areas
conformality (shape)
equivalence (area & scale)
minor – pertains to only 1 or 2 points
equidistant (distance)
azimuthal (direction)

10. Shape vs Area Conformality (shape) Equivalence (area)
retention of correct angles
requirements
meridians & parallels cross at right angles
misleading
small areas VS large areas
Equivalence (area) is lost
Equivalence (area)
unit area on map = same square unit on globe surface
characteristics
right angle crossing is lost
shape distorted

11. Minor Properties Equidistant (distance) equivalence (area) is lost
measure from center
others area are incorrect (significant amount)
equivalence (area) is lost
DO NOT measure distance on a map showing a large area unless it is equidistant

12. Minor Properties and Other
Azimuthal (direction)
true directions from 1 central point
others inaccurate
can preserve 1 other property
Other
Compromise
does not preserve any of the 4 main properties

13. Map Projections 4 general classes planar (azimuthal) cylindrical Conic
oval
and miscellaneous

14. Planar Projections (Azimuthal)
Flat sheet of paper
@ pole – polar aspect (simplest);
least distortion
@ mid-latitude – oblique aspect;
@ equator – equatorial aspect
Azimuthal projection
air navigational
hemispheres
No (minimal) modifications

15. Lambert Azimuthal Equal Area
Map large ocean areas
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

16. Oblique Aspect Orthographic Projection
Perspective views of hemispheres.
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

17. Cylindrical Projections
Tangent to line(s) on sphere
equator
Characteristics
meridians do not converge at poles
space parallels further apart
smaller area – shape preserved
Uses
atlases
map of the world

18. Behrmann Cylindrical Equal-Area
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

19. Peters Projection
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

20. Mercator Projection
Marine navigation
rhumb line

21. Miller Cylindrical Projection
Avoids scale exaggerations of the Mercator
shape & area distorted
true direction along equator
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

22. Conic Projections Cone enveloped around sphere
normal – cone is tangent along a chosen parallel
Area and shape preserved
Simple Conic & Polyconic
Uses:
areas w/ east-west extent
National Atlas of the United States of America

23. SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

24. Conic
Polyconic

25. Albers Equal Area Conic
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

26. Miscellaneous Projections
Unprojected Maps
distortion
scale,
distance,
area, &
shape
increases toward the poles

27. N. America: Unprojected Latitude and Longitude
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995
N. America: Unprojected Latitude and Longitude
World: Unprojected Latitude and Longitude
SOURCE: Peter H. Dana, Department of Geography, University of Texas at Austin, 1995

28. Choosing a Map Projection
1st step is to determine:
location
size
shape
These 3 determine where the area to be mapped falls in relation to the projections distortion
country in the tropics – cylindrical projection
country in the temperate zone – conical projection
polar area – planar projection

29. Choosing a Map Projection (2)
These global zones map into the areas in each projection where distortion is lowest:
Cylindricals are true at the equator and distortion increases toward the poles.
Conics are true along some parallel somewhere between the equator and a pole and distortion increases away from this standard.
Planar are true only at their center point, but generally distortion is worst at the edge of the map.
Can make other modifications